Classic Alfa Forums

Just did a 300 mile blast in my S2 sud.
It has a 1.5, 95 bhp engine.

Had rebore and new pistons and rings a bit back.
Exhaust smoke becoming evident on cold start up recently.

But on a long uphill road ,under load, quite a trail of smoke behind me.

I did wonder if one of the new rings had failed. But a comp test shows 210, 215, 220,220.

Could it be valve guides?
Or valve stem oil seals?

Ours does it as well, also on a long downhill section with the throttle closed. I suspect it’s valve stem oil seals.

Mine smoked on downhill with throttle closed. Changed valve stem seals no change Still smokes . Mine only had seals on the inlets was wondering if I should of put some on the exhausts valves.

I've bought a set of 8 valve stem oil seals.
But I wondered if worn valve guides were a common fault?

If you don’t have seals on the exhaust valves then it will still smoke.

Ian at Justsuds tells me that Sud valve guides rarely wear.
But to check for play by rocking side to side.

He also says to use 8 oil seals (sorry Craig!)

He stocks the oil seals, and can get the guides in to order.

When I take the engine out for the cars respray I will pop some in . It's funny how there are only four seals in a head gasket set and mine only had the seals on the inlets .

Correction.

Ian at Sudshop!

My valve guides were fine when my heads were overhauled, I only had seals on the inlet valves, but a new set of eight have been fitted, along with new exhaust valves.

As a quick rule, oil smoke on the throttle is combustion chamber leak by, ie oil scavenge and or piston rings, worn bore etc,

But off the throttle smoke, or immediately following a gear change, or idle at lights, junction etc you get a small cloud clearance pulling away, is usually valve stem seals, or at least a leak by in that area.


Usually!